The invention relates to improvements in methods of and in apparatus for manipulating running webs of paper or the like, and more particularly to improvements in methods of and in apparatus for dividing a running web of wrapping material, such as cigarette paper or other sheet-like or strip-shaped wrapping material in cigarette making, cigarette packing and analogous machines.
It is often necessary to split a running web of paper or the like into a plurality of (e.g., into two) identical strips. Such undertaking is a relatively simple procedure if the width of the web is always constant; however, problems can and do arise if the width of the web varies at times in an unpredictable manner in an apparatus or machine wherein the widths of the strips should be identical at all times or wherein the width of one of the strips should remain constant irrespective of variations in the width of a web which is to be severed or otherwise split into plural strips. Moreover, problems arise when a relatively thin web (such as a web of cigarette paper) is to be subdivided into plural strips without tearing, cracking, folding and at a high or very high speed such as is necessary or expected in a modern cigarette rod making machine, especially in a machine which is designed to simultaneously turn out several continuous cigarette rods each of which is ready to be subdivided into a series or file of successive cigarettes of unit length or multiple unit length.
In a so-called multiple-rod cigarette making machine, it is customary to split a running web of cigarette paper lengthwise into at least two discrete strips each of which is thereupon draped around a discrete rod-shaped filler of tobacco particles (e.g., shreds of tobacco leaf laminae). The web must be treated gently in order to avoid damage to the tubular wrappers of discrete cigarettes, to avoid misalignment of the strips in the wrapping mechanism, as well as to ensure identity of cigarettes regardless of whether they contain portions of the one or the other filler being turned out in a twin-rod cigarette maker. The situation is analogous in a machine which turns out filter rods of the type wherein a rod-like filler of filter material for tobacco smoke (such as cellulose acetate fibers) is confined in a strip of cigarette paper or other suitable wrapping material. The same holds true for packing machines wherein long series of arrayed groups of parallel plain or filter cigarettes, cigars or cigarillos are to be confined in converted blanks of paper, cardboard or other wrapping material and such blanks are obtained by subdividing running strips each of which is a part (such as one-half) of a running web of wrapping material. Splitting of webs of wrapping material is customary in packing machines which turn out so-called soft cigarette packs.
Presently known web splitting machines are disclosed, for example, in U.S. Pat. No. 4,960,234 (granted Oct. 2, 1990 to Focke for “APPARATUS FOR SEPARATING WEBS OF MATERIAL INTO (TWO) PART WEBS” and corresponding to European patent No. 0 309 818) and in U.S. Pat. No. 4,627,319 (granted Dec. 9, 1986 to Mattei et al. for “DEVICE FOR SUPPLYING WEBS OF WRAPPING MATERIAL TO A CIGARETTE MAKING MACHINE OF THE TWO ROD TYPE” and corresponding to German patent No. 35 02 009).